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<div class="section" id="module-simplejson">
<span id="simplejson-json-encoder-and-decoder"></span><h1><a class="reference internal" href="#module-simplejson" title="simplejson: Encode and decode the JSON format."><tt class="xref py py-mod docutils literal"><span class="pre">simplejson</span></tt></a> — JSON encoder and decoder<a class="headerlink" href="#module-simplejson" title="Permalink to this headline">¶</a></h1>
<p>JSON (JavaScript Object Notation) <<a class="reference external" href="http://json.org">http://json.org</a>> is a subset of JavaScript
syntax (ECMA-262 3rd edition) used as a lightweight data interchange format.</p>
<p><a class="reference internal" href="#module-simplejson" title="simplejson: Encode and decode the JSON format."><tt class="xref py py-mod docutils literal"><span class="pre">simplejson</span></tt></a> exposes an API familiar to users of the standard library
<tt class="xref py py-mod docutils literal"><span class="pre">marshal</span></tt> and <tt class="xref py py-mod docutils literal"><span class="pre">pickle</span></tt> modules. It is the externally maintained
version of the <tt class="xref py py-mod docutils literal"><span class="pre">json</span></tt> library contained in Python 2.6, but maintains
compatibility with Python 2.5 and (currently) has
significant performance advantages, even without using the optional C
extension for speedups. <a class="reference internal" href="#module-simplejson" title="simplejson: Encode and decode the JSON format."><tt class="xref py py-mod docutils literal"><span class="pre">simplejson</span></tt></a> is also supported on Python 3.3+.</p>
<p>Development of simplejson happens on Github:
<a class="reference external" href="http://github.com/simplejson/simplejson">http://github.com/simplejson/simplejson</a></p>
<p>Encoding basic Python object hierarchies:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">([</span><span class="s">'foo'</span><span class="p">,</span> <span class="p">{</span><span class="s">'bar'</span><span class="p">:</span> <span class="p">(</span><span class="s">'baz'</span><span class="p">,</span> <span class="bp">None</span><span class="p">,</span> <span class="mf">1.0</span><span class="p">,</span> <span class="mi">2</span><span class="p">)}])</span>
<span class="go">'["foo", {"bar": ["baz", null, 1.0, 2]}]'</span>
<span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="s">"</span><span class="se">\"</span><span class="s">foo</span><span class="se">\b</span><span class="s">ar"</span><span class="p">))</span>
<span class="go">"\"foo\bar"</span>
<span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="s">u'</span><span class="se">\u1234</span><span class="s">'</span><span class="p">))</span>
<span class="go">"\u1234"</span>
<span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="s">'</span><span class="se">\\</span><span class="s">'</span><span class="p">))</span>
<span class="go">"\\"</span>
<span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">({</span><span class="s">"c"</span><span class="p">:</span> <span class="mi">0</span><span class="p">,</span> <span class="s">"b"</span><span class="p">:</span> <span class="mi">0</span><span class="p">,</span> <span class="s">"a"</span><span class="p">:</span> <span class="mi">0</span><span class="p">},</span> <span class="n">sort_keys</span><span class="o">=</span><span class="bp">True</span><span class="p">))</span>
<span class="go">{"a": 0, "b": 0, "c": 0}</span>
<span class="gp">>>> </span><span class="kn">from</span> <span class="nn">simplejson.compat</span> <span class="kn">import</span> <span class="n">StringIO</span>
<span class="gp">>>> </span><span class="n">io</span> <span class="o">=</span> <span class="n">StringIO</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">dump</span><span class="p">([</span><span class="s">'streaming API'</span><span class="p">],</span> <span class="n">io</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">io</span><span class="o">.</span><span class="n">getvalue</span><span class="p">()</span>
<span class="go">'["streaming API"]'</span>
</pre></div>
</div>
<p>Compact encoding:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="n">obj</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,{</span><span class="s">'4'</span><span class="p">:</span> <span class="mi">5</span><span class="p">,</span> <span class="s">'6'</span><span class="p">:</span> <span class="mi">7</span><span class="p">}]</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="n">separators</span><span class="o">=</span><span class="p">(</span><span class="s">','</span><span class="p">,</span> <span class="s">':'</span><span class="p">),</span> <span class="n">sort_keys</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="go">'[1,2,3,{"4":5,"6":7}]'</span>
</pre></div>
</div>
<p>Pretty printing:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">({</span><span class="s">'4'</span><span class="p">:</span> <span class="mi">5</span><span class="p">,</span> <span class="s">'6'</span><span class="p">:</span> <span class="mi">7</span><span class="p">},</span> <span class="n">sort_keys</span><span class="o">=</span><span class="bp">True</span><span class="p">,</span> <span class="n">indent</span><span class="o">=</span><span class="mi">4</span> <span class="o">*</span> <span class="s">' '</span><span class="p">))</span>
<span class="go">{</span>
<span class="go"> "4": 5,</span>
<span class="go"> "6": 7</span>
<span class="go">}</span>
</pre></div>
</div>
<p>Decoding JSON:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="n">obj</span> <span class="o">=</span> <span class="p">[</span><span class="s">u'foo'</span><span class="p">,</span> <span class="p">{</span><span class="s">u'bar'</span><span class="p">:</span> <span class="p">[</span><span class="s">u'baz'</span><span class="p">,</span> <span class="bp">None</span><span class="p">,</span> <span class="mf">1.0</span><span class="p">,</span> <span class="mi">2</span><span class="p">]}]</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="s">'["foo", {"bar":["baz", null, 1.0, 2]}]'</span><span class="p">)</span> <span class="o">==</span> <span class="n">obj</span>
<span class="go">True</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="s">'"</span><span class="se">\\</span><span class="s">"foo</span><span class="se">\\</span><span class="s">bar"'</span><span class="p">)</span> <span class="o">==</span> <span class="s">u'"foo</span><span class="se">\x08</span><span class="s">ar'</span>
<span class="go">True</span>
<span class="gp">>>> </span><span class="kn">from</span> <span class="nn">simplejson.compat</span> <span class="kn">import</span> <span class="n">StringIO</span>
<span class="gp">>>> </span><span class="n">io</span> <span class="o">=</span> <span class="n">StringIO</span><span class="p">(</span><span class="s">'["streaming API"]'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">load</span><span class="p">(</span><span class="n">io</span><span class="p">)[</span><span class="mi">0</span><span class="p">]</span> <span class="o">==</span> <span class="s">'streaming API'</span>
<span class="go">True</span>
</pre></div>
</div>
<p>Using Decimal instead of float:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="kn">from</span> <span class="nn">decimal</span> <span class="kn">import</span> <span class="n">Decimal</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="s">'1.1'</span><span class="p">,</span> <span class="n">use_decimal</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span> <span class="o">==</span> <span class="n">Decimal</span><span class="p">(</span><span class="s">'1.1'</span><span class="p">)</span>
<span class="go">True</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="n">Decimal</span><span class="p">(</span><span class="s">'1.1'</span><span class="p">),</span> <span class="n">use_decimal</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span> <span class="o">==</span> <span class="s">'1.1'</span>
<span class="go">True</span>
</pre></div>
</div>
<p>Specializing JSON object decoding:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="k">def</span> <span class="nf">as_complex</span><span class="p">(</span><span class="n">dct</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">if</span> <span class="s">'__complex__'</span> <span class="ow">in</span> <span class="n">dct</span><span class="p">:</span>
<span class="gp">... </span> <span class="k">return</span> <span class="nb">complex</span><span class="p">(</span><span class="n">dct</span><span class="p">[</span><span class="s">'real'</span><span class="p">],</span> <span class="n">dct</span><span class="p">[</span><span class="s">'imag'</span><span class="p">])</span>
<span class="gp">... </span> <span class="k">return</span> <span class="n">dct</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="s">'{"__complex__": true, "real": 1, "imag": 2}'</span><span class="p">,</span>
<span class="gp">... </span> <span class="n">object_hook</span><span class="o">=</span><span class="n">as_complex</span><span class="p">)</span>
<span class="go">(1+2j)</span>
<span class="gp">>>> </span><span class="kn">import</span> <span class="nn">decimal</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">loads</span><span class="p">(</span><span class="s">'1.1'</span><span class="p">,</span> <span class="n">parse_float</span><span class="o">=</span><span class="n">decimal</span><span class="o">.</span><span class="n">Decimal</span><span class="p">)</span> <span class="o">==</span> <span class="n">decimal</span><span class="o">.</span><span class="n">Decimal</span><span class="p">(</span><span class="s">'1.1'</span><span class="p">)</span>
<span class="go">True</span>
</pre></div>
</div>
<p>Specializing JSON object encoding:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="k">def</span> <span class="nf">encode_complex</span><span class="p">(</span><span class="n">obj</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="nb">complex</span><span class="p">):</span>
<span class="gp">... </span> <span class="k">return</span> <span class="p">[</span><span class="n">obj</span><span class="o">.</span><span class="n">real</span><span class="p">,</span> <span class="n">obj</span><span class="o">.</span><span class="n">imag</span><span class="p">]</span>
<span class="gp">... </span> <span class="k">raise</span> <span class="ne">TypeError</span><span class="p">(</span><span class="nb">repr</span><span class="p">(</span><span class="n">o</span><span class="p">)</span> <span class="o">+</span> <span class="s">" is not JSON serializable"</span><span class="p">)</span>
<span class="gp">...</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">1j</span><span class="p">,</span> <span class="n">default</span><span class="o">=</span><span class="n">encode_complex</span><span class="p">)</span>
<span class="go">'[2.0, 1.0]'</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">JSONEncoder</span><span class="p">(</span><span class="n">default</span><span class="o">=</span><span class="n">encode_complex</span><span class="p">)</span><span class="o">.</span><span class="n">encode</span><span class="p">(</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">1j</span><span class="p">)</span>
<span class="go">'[2.0, 1.0]'</span>
<span class="gp">>>> </span><span class="s">''</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">json</span><span class="o">.</span><span class="n">JSONEncoder</span><span class="p">(</span><span class="n">default</span><span class="o">=</span><span class="n">encode_complex</span><span class="p">)</span><span class="o">.</span><span class="n">iterencode</span><span class="p">(</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">1j</span><span class="p">))</span>
<span class="go">'[2.0, 1.0]'</span>
</pre></div>
</div>
<p>Using <tt class="xref py py-mod docutils literal"><span class="pre">simplejson.tool</span></tt> from the shell to validate and pretty-print:</p>
<div class="highlight-none"><div class="highlight"><pre>$ echo '{"json":"obj"}' | python -m simplejson.tool
{
"json": "obj"
}
$ echo '{ 1.2:3.4}' | python -m simplejson.tool
Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
</pre></div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The JSON produced by this module’s default settings is a subset of
YAML, so it may be used as a serializer for that as well.</p>
</div>
<div class="section" id="basic-usage">
<h2>Basic Usage<a class="headerlink" href="#basic-usage" title="Permalink to this headline">¶</a></h2>
<dl class="function">
<dt id="simplejson.dump">
<tt class="descclassname">simplejson.</tt><tt class="descname">dump</tt><big>(</big><em>obj</em>, <em>fp</em><span class="optional">[</span>, <em>skipkeys</em><span class="optional">[</span>, <em>ensure_ascii</em><span class="optional">[</span>, <em>check_circular</em><span class="optional">[</span>, <em>allow_nan</em><span class="optional">[</span>, <em>cls</em><span class="optional">[</span>, <em>indent</em><span class="optional">[</span>, <em>separators</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>default</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>namedtuple_as_object</em><span class="optional">[</span>, <em>tuple_as_array</em><span class="optional">[</span>, <em>bigint_as_string</em><span class="optional">[</span>, <em>sort_keys</em><span class="optional">[</span>, <em>item_sort_key</em><span class="optional">[</span><span class="optional">[</span>, <em>for_json</em><span class="optional">[</span>, <em>ignore_nan</em><span class="optional">[</span>, <em>**kw</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.dump" title="Permalink to this definition">¶</a></dt>
<dd><blockquote>
<div><p>Serialize <em>obj</em> as a JSON formatted stream to <em>fp</em> (a <tt class="docutils literal"><span class="pre">.write()</span></tt>-supporting
file-like object).</p>
<p>If <em>skipkeys</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), then dict keys that are not
of a basic type (<tt class="xref py py-class docutils literal"><span class="pre">str</span></tt>, <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt>, <tt class="xref py py-class docutils literal"><span class="pre">int</span></tt>, <tt class="xref py py-class docutils literal"><span class="pre">long</span></tt>,
<tt class="xref py py-class docutils literal"><span class="pre">float</span></tt>, <tt class="xref py py-class docutils literal"><span class="pre">bool</span></tt>, <tt class="docutils literal"><span class="pre">None</span></tt>) will be skipped instead of raising a
<tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>.</p>
<p>If <em>ensure_ascii</em> is false (default: <tt class="docutils literal"><span class="pre">True</span></tt>), then some chunks written
to <em>fp</em> may be <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> instances, subject to normal Python
<tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> coercion rules. Unless <tt class="docutils literal"><span class="pre">fp.write()</span></tt>
explicitly understands <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> (as in <tt class="xref py py-func docutils literal"><span class="pre">codecs.getwriter()</span></tt>) this
is likely to cause an error. It’s best to leave the default settings, because
they are safe and it is highly optimized.</p>
<p>If <em>check_circular</em> is false (default: <tt class="docutils literal"><span class="pre">True</span></tt>), then the circular
reference check for container types will be skipped and a circular reference
will result in an <tt class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></tt> (or worse).</p>
<p>If <em>allow_nan</em> is false (default: <tt class="docutils literal"><span class="pre">True</span></tt>), then it will be a
<tt class="xref py py-exc docutils literal"><span class="pre">ValueError</span></tt> to serialize out of range <tt class="xref py py-class docutils literal"><span class="pre">float</span></tt> values (<tt class="docutils literal"><span class="pre">nan</span></tt>,
<tt class="docutils literal"><span class="pre">inf</span></tt>, <tt class="docutils literal"><span class="pre">-inf</span></tt>) in strict compliance of the original JSON specification.
If <em>allow_nan</em> is true, their JavaScript equivalents will be used
(<tt class="docutils literal"><span class="pre">NaN</span></tt>, <tt class="docutils literal"><span class="pre">Infinity</span></tt>, <tt class="docutils literal"><span class="pre">-Infinity</span></tt>). See also <em>ignore_nan</em> for ECMA-262
compliant behavior.</p>
<p>If <em>indent</em> is a string, then JSON array elements and object members
will be pretty-printed with a newline followed by that string repeated
for each level of nesting. <tt class="docutils literal"><span class="pre">None</span></tt> (the default) selects the most compact
representation without any newlines. For backwards compatibility with
versions of simplejson earlier than 2.1.0, an integer is also accepted
and is converted to a string with that many spaces.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span>Changed <em>indent</em> from an integer number of spaces to a string.</p>
<p>If specified, <em>separators</em> should be an <tt class="docutils literal"><span class="pre">(item_separator,</span> <span class="pre">key_separator)</span></tt>
tuple. The default is <tt class="docutils literal"><span class="pre">(',</span> <span class="pre">',</span> <span class="pre">':</span> <span class="pre">')</span></tt> if <em>indent</em> is <tt class="docutils literal"><span class="pre">None</span></tt> and
<tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':</span> <span class="pre">')</span></tt> otherwise. To get the most compact JSON representation,
you should specify <tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':')</span></tt> to eliminate whitespace.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.4: </span>Use <tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':</span> <span class="pre">')</span></tt> as default if <em>indent</em> is not <tt class="docutils literal"><span class="pre">None</span></tt>.</p>
<p><em>encoding</em> is the character encoding for str instances, default is
<tt class="docutils literal"><span class="pre">'utf-8'</span></tt>.</p>
<p><em>default(obj)</em> is a function that should return a serializable version of
<em>obj</em> or raise <tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>. The default simply raises <tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>.</p>
<p>To use a custom <a class="reference internal" href="#simplejson.JSONEncoder" title="simplejson.JSONEncoder"><tt class="xref py py-class docutils literal"><span class="pre">JSONEncoder</span></tt></a> subclass (e.g. one that overrides the
<tt class="xref py py-meth docutils literal"><span class="pre">default()</span></tt> method to serialize additional types), specify it with the
<em>cls</em> kwarg.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Subclassing is not recommended. Use the <em>default</em> kwarg
or <em>for_json</em> instead. This is faster and more portable.</p>
</div>
<p>If <em>use_decimal</em> is true (default: <tt class="docutils literal"><span class="pre">True</span></tt>) then <tt class="xref py py-class docutils literal"><span class="pre">decimal.Decimal</span></tt>
will be natively serialized to JSON with full precision.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span><em>use_decimal</em> is new in 2.1.0.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span>The default of <em>use_decimal</em> changed to <tt class="docutils literal"><span class="pre">True</span></tt> in 2.2.0.</p>
<p>If <em>namedtuple_as_object</em> is true (default: <tt class="docutils literal"><span class="pre">True</span></tt>),
objects with <tt class="docutils literal"><span class="pre">_asdict()</span></tt> methods will be encoded
as JSON objects.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span><em>namedtuple_as_object</em> is new in 2.2.0.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.3.0: </span><em>namedtuple_as_object</em> no longer requires that these objects be
subclasses of <tt class="xref py py-class docutils literal"><span class="pre">tuple</span></tt>.</p>
<p>If <em>tuple_as_array</em> is true (default: <tt class="docutils literal"><span class="pre">True</span></tt>),
<tt class="xref py py-class docutils literal"><span class="pre">tuple</span></tt> (and subclasses) will be encoded as JSON arrays.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span><em>tuple_as_array</em> is new in 2.2.0.</p>
<p>If <em>bigint_as_string</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), <tt class="xref py py-class docutils literal"><span class="pre">int`</span></tt> <tt class="docutils literal"><span class="pre">2**53</span></tt>
and higher or lower than <tt class="docutils literal"><span class="pre">-2**53</span></tt> will be encoded as strings. This is to
avoid the rounding that happens in Javascript otherwise. Note that this
option loses type information, so use with extreme caution.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.4.0: </span><em>bigint_as_string</em> is new in 2.4.0.</p>
<p>If <em>sort_keys</em> is true (not the default), then the output of dictionaries
will be sorted by key; this is useful for regression tests to ensure that
JSON serializations can be compared on a day-to-day basis.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.0.0: </span>Sorting now happens after the keys have been coerced to
strings, to avoid comparison of heterogeneously typed objects
(since this does not work in Python 3.3+)</p>
<p>If <em>item_sort_key</em> is a callable (not the default), then the output of
dictionaries will be sorted with it. The callable will be used like this:
<tt class="docutils literal"><span class="pre">sorted(dct.items(),</span> <span class="pre">key=item_sort_key)</span></tt>. This option takes precedence
over <em>sort_keys</em>.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5.0: </span><em>item_sort_key</em> is new in 2.5.0.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.0.0: </span>Sorting now happens after the keys have been coerced to
strings, to avoid comparison of heterogeneously typed objects
(since this does not work in Python 3.3+)</p>
<p>If <em>for_json</em> is true (not the default), objects with a <tt class="docutils literal"><span class="pre">for_json()</span></tt>
method will use the return value of that method for encoding as JSON instead
of the object.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.2.0: </span><em>for_json</em> is new in 3.2.0.</p>
<p>If <em>ignore_nan</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), then out of range
<tt class="xref py py-class docutils literal"><span class="pre">float</span></tt> values (<tt class="docutils literal"><span class="pre">nan</span></tt>, <tt class="docutils literal"><span class="pre">inf</span></tt>, <tt class="docutils literal"><span class="pre">-inf</span></tt>) will be serialized as
<tt class="docutils literal"><span class="pre">null</span></tt> in compliance with the ECMA-262 specification. If true, this will
override <em>allow_nan</em>.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.2.0: </span><em>ignore_nan</em> is new in 3.2.0.</p>
</div></blockquote>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">JSON is not a framed protocol so unlike <tt class="xref py py-mod docutils literal"><span class="pre">pickle</span></tt> or <tt class="xref py py-mod docutils literal"><span class="pre">marshal</span></tt> it
does not make sense to serialize more than one JSON document without some
container protocol to delimit them.</p>
</div>
</dd></dl>
<dl class="function">
<dt id="simplejson.dumps">
<tt class="descclassname">simplejson.</tt><tt class="descname">dumps</tt><big>(</big><em>obj</em><span class="optional">[</span>, <em>skipkeys</em><span class="optional">[</span>, <em>ensure_ascii</em><span class="optional">[</span>, <em>check_circular</em><span class="optional">[</span>, <em>allow_nan</em><span class="optional">[</span>, <em>cls</em><span class="optional">[</span>, <em>indent</em><span class="optional">[</span>, <em>separators</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>default</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>namedtuple_as_object</em><span class="optional">[</span>, <em>tuple_as_array</em><span class="optional">[</span>, <em>bigint_as_string</em><span class="optional">[</span>, <em>sort_keys</em><span class="optional">[</span>, <em>item_sort_key</em><span class="optional">[</span>, <em>for_json</em><span class="optional">[</span>, <em>ignore_nan</em><span class="optional">[</span>, <em>**kw</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.dumps" title="Permalink to this definition">¶</a></dt>
<dd><p>Serialize <em>obj</em> to a JSON formatted <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt>.</p>
<p>If <em>ensure_ascii</em> is false, then the return value will be a
<tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> instance. The other arguments have the same meaning as in
<a class="reference internal" href="#simplejson.dump" title="simplejson.dump"><tt class="xref py py-func docutils literal"><span class="pre">dump()</span></tt></a>. Note that the default <em>ensure_ascii</em> setting has much
better performance.</p>
<p>The other options have the same meaning as in <a class="reference internal" href="#simplejson.dump" title="simplejson.dump"><tt class="xref py py-func docutils literal"><span class="pre">dump()</span></tt></a>.</p>
</dd></dl>
<dl class="function">
<dt id="simplejson.load">
<tt class="descclassname">simplejson.</tt><tt class="descname">load</tt><big>(</big><em>fp</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>cls</em><span class="optional">[</span>, <em>object_hook</em><span class="optional">[</span>, <em>parse_float</em><span class="optional">[</span>, <em>parse_int</em><span class="optional">[</span>, <em>parse_constant</em><span class="optional">[</span>, <em>object_pairs_hook</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>**kw</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.load" title="Permalink to this definition">¶</a></dt>
<dd><p>Deserialize <em>fp</em> (a <tt class="docutils literal"><span class="pre">.read()</span></tt>-supporting file-like object containing a JSON
document) to a Python object. <a class="reference internal" href="#simplejson.JSONDecodeError" title="simplejson.JSONDecodeError"><tt class="xref py py-exc docutils literal"><span class="pre">JSONDecodeError</span></tt></a> will be
raised if the given JSON document is not valid.</p>
<p>If the contents of <em>fp</em> are encoded with an ASCII based encoding other than
UTF-8 (e.g. latin-1), then an appropriate <em>encoding</em> name must be specified.
Encodings that are not ASCII based (such as UCS-2) are not allowed, and
should be wrapped with <tt class="docutils literal"><span class="pre">codecs.getreader(fp)(encoding)</span></tt>, or simply decoded
to a <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> object and passed to <a class="reference internal" href="#simplejson.loads" title="simplejson.loads"><tt class="xref py py-func docutils literal"><span class="pre">loads()</span></tt></a>. The default
setting of <tt class="docutils literal"><span class="pre">'utf-8'</span></tt> is fastest and should be using whenever possible.</p>
<p>If <em>fp.read()</em> returns <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> then decoded JSON strings that contain
only ASCII characters may be parsed as <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> for performance and
memory reasons. If your code expects only <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> the appropriate
solution is to wrap fp with a reader as demonstrated above.</p>
<p><em>object_hook</em> is an optional function that will be called with the result of
any object literal decode (a <tt class="xref py py-class docutils literal"><span class="pre">dict</span></tt>). The return value of
<em>object_hook</em> will be used instead of the <tt class="xref py py-class docutils literal"><span class="pre">dict</span></tt>. This feature can be used
to implement custom decoders (e.g. JSON-RPC class hinting).</p>
<p><em>object_pairs_hook</em> is an optional function that will be called with the
result of any object literal decode with an ordered list of pairs. The
return value of <em>object_pairs_hook</em> will be used instead of the
<tt class="xref py py-class docutils literal"><span class="pre">dict</span></tt>. This feature can be used to implement custom decoders that
rely on the order that the key and value pairs are decoded (for example,
<tt class="xref py py-class docutils literal"><span class="pre">collections.OrderedDict</span></tt> will remember the order of insertion). If
<em>object_hook</em> is also defined, the <em>object_pairs_hook</em> takes priority.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span>Added support for <em>object_pairs_hook</em>.</p>
<p><em>parse_float</em>, if specified, will be called with the string of every JSON
float to be decoded. By default, this is equivalent to <tt class="docutils literal"><span class="pre">float(num_str)</span></tt>.
This can be used to use another datatype or parser for JSON floats
(e.g. <tt class="xref py py-class docutils literal"><span class="pre">decimal.Decimal</span></tt>).</p>
<p><em>parse_int</em>, if specified, will be called with the string of every JSON int
to be decoded. By default, this is equivalent to <tt class="docutils literal"><span class="pre">int(num_str)</span></tt>. This can
be used to use another datatype or parser for JSON integers
(e.g. <tt class="xref py py-class docutils literal"><span class="pre">float</span></tt>).</p>
<p><em>parse_constant</em>, if specified, will be called with one of the following
strings: <tt class="docutils literal"><span class="pre">'-Infinity'</span></tt>, <tt class="docutils literal"><span class="pre">'Infinity'</span></tt>, <tt class="docutils literal"><span class="pre">'NaN'</span></tt>. This can be used to
raise an exception if invalid JSON numbers are encountered.</p>
<p>If <em>use_decimal</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>) then <em>parse_float</em> is set to
<tt class="xref py py-class docutils literal"><span class="pre">decimal.Decimal</span></tt>. This is a convenience for parity with the
<a class="reference internal" href="#simplejson.dump" title="simplejson.dump"><tt class="xref py py-func docutils literal"><span class="pre">dump()</span></tt></a> parameter.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span><em>use_decimal</em> is new in 2.1.0.</p>
<p>To use a custom <a class="reference internal" href="#simplejson.JSONDecoder" title="simplejson.JSONDecoder"><tt class="xref py py-class docutils literal"><span class="pre">JSONDecoder</span></tt></a> subclass, specify it with the <tt class="docutils literal"><span class="pre">cls</span></tt>
kwarg. Additional keyword arguments will be passed to the constructor of the
class. You probably shouldn’t do this.</p>
<blockquote>
<div><div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Subclassing is not recommended. You should use <em>object_hook</em> or
<em>object_pairs_hook</em>. This is faster and more portable than subclassing.</p>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last"><a class="reference internal" href="#simplejson.load" title="simplejson.load"><tt class="xref py py-func docutils literal"><span class="pre">load()</span></tt></a> will read the rest of the file-like object as a string and
then call <a class="reference internal" href="#simplejson.loads" title="simplejson.loads"><tt class="xref py py-func docutils literal"><span class="pre">loads()</span></tt></a>. It does not stop at the end of the first valid
JSON document it finds and it will raise an error if there is anything
other than whitespace after the document. Except for files containing
only one JSON document, it is recommended to use <a class="reference internal" href="#simplejson.loads" title="simplejson.loads"><tt class="xref py py-func docutils literal"><span class="pre">loads()</span></tt></a>.</p>
</div>
</div></blockquote>
</dd></dl>
<dl class="function">
<dt id="simplejson.loads">
<tt class="descclassname">simplejson.</tt><tt class="descname">loads</tt><big>(</big><em>s</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>cls</em><span class="optional">[</span>, <em>object_hook</em><span class="optional">[</span>, <em>parse_float</em><span class="optional">[</span>, <em>parse_int</em><span class="optional">[</span>, <em>parse_constant</em><span class="optional">[</span>, <em>object_pairs_hook</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>**kw</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.loads" title="Permalink to this definition">¶</a></dt>
<dd><p>Deserialize <em>s</em> (a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> or <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> instance containing a JSON
document) to a Python object. <a class="reference internal" href="#simplejson.JSONDecodeError" title="simplejson.JSONDecodeError"><tt class="xref py py-exc docutils literal"><span class="pre">JSONDecodeError</span></tt></a> will be
raised if the given JSON document is not valid.</p>
<p>If <em>s</em> is a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> instance and is encoded with an ASCII based encoding
other than UTF-8 (e.g. latin-1), then an appropriate <em>encoding</em> name must be
specified. Encodings that are not ASCII based (such as UCS-2) are not
allowed and should be decoded to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> first.</p>
<p>If <em>s</em> is a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> then decoded JSON strings that contain
only ASCII characters may be parsed as <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> for performance and
memory reasons. If your code expects only <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> the appropriate
solution is decode <em>s</em> to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> prior to calling loads.</p>
<p>The other arguments have the same meaning as in <a class="reference internal" href="#simplejson.load" title="simplejson.load"><tt class="xref py py-func docutils literal"><span class="pre">load()</span></tt></a>.</p>
</dd></dl>
</div>
<div class="section" id="encoders-and-decoders">
<h2>Encoders and decoders<a class="headerlink" href="#encoders-and-decoders" title="Permalink to this headline">¶</a></h2>
<dl class="class">
<dt id="simplejson.JSONDecoder">
<em class="property">class </em><tt class="descclassname">simplejson.</tt><tt class="descname">JSONDecoder</tt><big>(</big><span class="optional">[</span><em>encoding</em><span class="optional">[</span>, <em>object_hook</em><span class="optional">[</span>, <em>parse_float</em><span class="optional">[</span>, <em>parse_int</em><span class="optional">[</span>, <em>parse_constant</em><span class="optional">[</span>, <em>object_pairs_hook</em><span class="optional">[</span>, <em>strict</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.JSONDecoder" title="Permalink to this definition">¶</a></dt>
<dd><p>Simple JSON decoder.</p>
<p>Performs the following translations in decoding by default:</p>
<table border="1" class="docutils">
<colgroup>
<col width="44%" />
<col width="56%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">JSON</th>
<th class="head">Python</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td>object</td>
<td>dict</td>
</tr>
<tr class="row-odd"><td>array</td>
<td>list</td>
</tr>
<tr class="row-even"><td>string</td>
<td>unicode</td>
</tr>
<tr class="row-odd"><td>number (int)</td>
<td>int, long</td>
</tr>
<tr class="row-even"><td>number (real)</td>
<td>float</td>
</tr>
<tr class="row-odd"><td>true</td>
<td>True</td>
</tr>
<tr class="row-even"><td>false</td>
<td>False</td>
</tr>
<tr class="row-odd"><td>null</td>
<td>None</td>
</tr>
</tbody>
</table>
<p>It also understands <tt class="docutils literal"><span class="pre">NaN</span></tt>, <tt class="docutils literal"><span class="pre">Infinity</span></tt>, and <tt class="docutils literal"><span class="pre">-Infinity</span></tt> as their
corresponding <tt class="docutils literal"><span class="pre">float</span></tt> values, which is outside the JSON spec.</p>
<p><em>encoding</em> determines the encoding used to interpret any <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> objects
decoded by this instance (<tt class="docutils literal"><span class="pre">'utf-8'</span></tt> by default). It has no effect when decoding
<tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> objects.</p>
<p>Note that currently only encodings that are a superset of ASCII work, strings
of other encodings should be passed in as <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt>.</p>
<p><em>object_hook</em> is an optional function that will be called with the result of
every JSON object decoded and its return value will be used in place of the
given <tt class="xref py py-class docutils literal"><span class="pre">dict</span></tt>. This can be used to provide custom deserializations
(e.g. to support JSON-RPC class hinting).</p>
<p><em>object_pairs_hook</em> is an optional function that will be called with the
result of any object literal decode with an ordered list of pairs. The
return value of <em>object_pairs_hook</em> will be used instead of the
<tt class="xref py py-class docutils literal"><span class="pre">dict</span></tt>. This feature can be used to implement custom decoders that
rely on the order that the key and value pairs are decoded (for example,
<tt class="xref py py-class docutils literal"><span class="pre">collections.OrderedDict</span></tt> will remember the order of insertion). If
<em>object_hook</em> is also defined, the <em>object_pairs_hook</em> takes priority.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span>Added support for <em>object_pairs_hook</em>.</p>
<p><em>parse_float</em>, if specified, will be called with the string of every JSON
float to be decoded. By default, this is equivalent to <tt class="docutils literal"><span class="pre">float(num_str)</span></tt>.
This can be used to use another datatype or parser for JSON floats
(e.g. <tt class="xref py py-class docutils literal"><span class="pre">decimal.Decimal</span></tt>).</p>
<p><em>parse_int</em>, if specified, will be called with the string of every JSON int
to be decoded. By default, this is equivalent to <tt class="docutils literal"><span class="pre">int(num_str)</span></tt>. This can
be used to use another datatype or parser for JSON integers
(e.g. <tt class="xref py py-class docutils literal"><span class="pre">float</span></tt>).</p>
<p><em>parse_constant</em>, if specified, will be called with one of the following
strings: <tt class="docutils literal"><span class="pre">'-Infinity'</span></tt>, <tt class="docutils literal"><span class="pre">'Infinity'</span></tt>, <tt class="docutils literal"><span class="pre">'NaN'</span></tt>. This can be used to
raise an exception if invalid JSON numbers are encountered.</p>
<p><em>strict</em> controls the parser’s behavior when it encounters an invalid
control character in a string. The default setting of <tt class="docutils literal"><span class="pre">True</span></tt> means that
unescaped control characters are parse errors, if <tt class="docutils literal"><span class="pre">False</span></tt> then control
characters will be allowed in strings.</p>
<dl class="method">
<dt id="simplejson.JSONDecoder.decode">
<tt class="descname">decode</tt><big>(</big><em>s</em><big>)</big><a class="headerlink" href="#simplejson.JSONDecoder.decode" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the Python representation of <em>s</em> (a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> or
<tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> instance containing a JSON document)</p>
<p>If <em>s</em> is a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> then decoded JSON strings that contain
only ASCII characters may be parsed as <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> for performance and
memory reasons. If your code expects only <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> the
appropriate solution is decode <em>s</em> to <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt> prior to calling
decode.</p>
<p><a class="reference internal" href="#simplejson.JSONDecodeError" title="simplejson.JSONDecodeError"><tt class="xref py py-exc docutils literal"><span class="pre">JSONDecodeError</span></tt></a> will be raised if the given JSON
document is not valid.</p>
</dd></dl>
<dl class="method">
<dt id="simplejson.JSONDecoder.raw_decode">
<tt class="descname">raw_decode</tt><big>(</big><em>s</em><span class="optional">[</span>, <em>idx=0</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.JSONDecoder.raw_decode" title="Permalink to this definition">¶</a></dt>
<dd><p>Decode a JSON document from <em>s</em> (a <tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> or <tt class="xref py py-class docutils literal"><span class="pre">unicode</span></tt>
beginning with a JSON document) starting from the index <em>idx</em> and return
a 2-tuple of the Python representation and the index in <em>s</em> where the
document ended.</p>
<p>This can be used to decode a JSON document from a string that may have
extraneous data at the end, or to decode a string that has a series of
JSON objects.</p>
<p><a class="reference internal" href="#simplejson.JSONDecodeError" title="simplejson.JSONDecodeError"><tt class="xref py py-exc docutils literal"><span class="pre">JSONDecodeError</span></tt></a> will be raised if the given JSON
document is not valid.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="simplejson.JSONEncoder">
<em class="property">class </em><tt class="descclassname">simplejson.</tt><tt class="descname">JSONEncoder</tt><big>(</big><span class="optional">[</span><em>skipkeys</em><span class="optional">[</span>, <em>ensure_ascii</em><span class="optional">[</span>, <em>check_circular</em><span class="optional">[</span>, <em>allow_nan</em><span class="optional">[</span>, <em>sort_keys</em><span class="optional">[</span>, <em>indent</em><span class="optional">[</span>, <em>separators</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>default</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>namedtuple_as_object</em><span class="optional">[</span>, <em>tuple_as_array</em><span class="optional">[</span>, <em>bigint_as_string</em><span class="optional">[</span>, <em>item_sort_key</em><span class="optional">[</span>, <em>for_json</em><span class="optional">[</span>, <em>ignore_nan</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.JSONEncoder" title="Permalink to this definition">¶</a></dt>
<dd><p>Extensible JSON encoder for Python data structures.</p>
<p>Supports the following objects and types by default:</p>
<table border="1" class="docutils">
<colgroup>
<col width="56%" />
<col width="44%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Python</th>
<th class="head">JSON</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td>dict, namedtuple</td>
<td>object</td>
</tr>
<tr class="row-odd"><td>list, tuple</td>
<td>array</td>
</tr>
<tr class="row-even"><td>str, unicode</td>
<td>string</td>
</tr>
<tr class="row-odd"><td>int, long, float</td>
<td>number</td>
</tr>
<tr class="row-even"><td>True</td>
<td>true</td>
</tr>
<tr class="row-odd"><td>False</td>
<td>false</td>
</tr>
<tr class="row-even"><td>None</td>
<td>null</td>
</tr>
</tbody>
</table>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span>Changed <em>namedtuple</em> encoding from JSON array to object.</p>
<p>To extend this to recognize other objects, subclass and implement a
<a class="reference internal" href="#simplejson.JSONEncoder.default" title="simplejson.JSONEncoder.default"><tt class="xref py py-meth docutils literal"><span class="pre">default()</span></tt></a> method with another method that returns a serializable object
for <tt class="docutils literal"><span class="pre">o</span></tt> if possible, otherwise it should call the superclass implementation
(to raise <tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>).</p>
<blockquote>
<div><div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Subclassing is not recommended. You should use the <em>default</em>
or <em>for_json</em> kwarg. This is faster and more portable than subclassing.</p>
</div>
</div></blockquote>
<p>If <em>skipkeys</em> is false (the default), then it is a <tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt> to
attempt encoding of keys that are not str, int, long, float or None. If
<em>skipkeys</em> is true, such items are simply skipped.</p>
<p>If <em>ensure_ascii</em> is true (the default), the output is guaranteed to be
<tt class="xref py py-class docutils literal"><span class="pre">str</span></tt> objects with all incoming unicode characters escaped. If
<em>ensure_ascii</em> is false, the output will be a unicode object.</p>
<p>If <em>check_circular</em> is false (the default), then lists, dicts, and custom
encoded objects will be checked for circular references during encoding to
prevent an infinite recursion (which would cause an <tt class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></tt>).
Otherwise, no such check takes place.</p>
<p>If <em>allow_nan</em> is true (the default), then <tt class="docutils literal"><span class="pre">NaN</span></tt>, <tt class="docutils literal"><span class="pre">Infinity</span></tt>, and
<tt class="docutils literal"><span class="pre">-Infinity</span></tt> will be encoded as such. This behavior is not JSON
specification compliant, but is consistent with most JavaScript based
encoders and decoders. Otherwise, it will be a <tt class="xref py py-exc docutils literal"><span class="pre">ValueError</span></tt> to encode
such floats. See also <em>ignore_nan</em> for ECMA-262 compliant behavior.</p>
<p>If <em>sort_keys</em> is true (not the default), then the output of dictionaries
will be sorted by key; this is useful for regression tests to ensure that
JSON serializations can be compared on a day-to-day basis.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.0.0: </span>Sorting now happens after the keys have been coerced to
strings, to avoid comparison of heterogeneously typed objects
(since this does not work in Python 3.3+)</p>
<p>If <em>item_sort_key</em> is a callable (not the default), then the output of
dictionaries will be sorted with it. The callable will be used like this:
<tt class="docutils literal"><span class="pre">sorted(dct.items(),</span> <span class="pre">key=item_sort_key)</span></tt>. This option takes precedence
over <em>sort_keys</em>.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5.0: </span><em>item_sort_key</em> is new in 2.5.0.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.0.0: </span>Sorting now happens after the keys have been coerced to
strings, to avoid comparison of heterogeneously typed objects
(since this does not work in Python 3.3+)</p>
<p>If <em>indent</em> is a string, then JSON array elements and object members
will be pretty-printed with a newline followed by that string repeated
for each level of nesting. <tt class="docutils literal"><span class="pre">None</span></tt> (the default) selects the most compact
representation without any newlines. For backwards compatibility with
versions of simplejson earlier than 2.1.0, an integer is also accepted
and is converted to a string with that many spaces.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span>Changed <em>indent</em> from an integer number of spaces to a string.</p>
<p>If specified, <em>separators</em> should be an <tt class="docutils literal"><span class="pre">(item_separator,</span> <span class="pre">key_separator)</span></tt>
tuple. The default is <tt class="docutils literal"><span class="pre">(',</span> <span class="pre">',</span> <span class="pre">':</span> <span class="pre">')</span></tt>. To get the most compact JSON
representation, you should specify <tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':')</span></tt> to eliminate whitespace.
tuple. The default is <tt class="docutils literal"><span class="pre">(',</span> <span class="pre">',</span> <span class="pre">':</span> <span class="pre">')</span></tt> if <em>indent</em> is <tt class="docutils literal"><span class="pre">None</span></tt> and
<tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':</span> <span class="pre">')</span></tt> otherwise. To get the most compact JSON representation,
you should specify <tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':')</span></tt> to eliminate whitespace.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.4: </span>Use <tt class="docutils literal"><span class="pre">(',',</span> <span class="pre">':</span> <span class="pre">')</span></tt> as default if <em>indent</em> is not <tt class="docutils literal"><span class="pre">None</span></tt>.</p>
<p>If specified, <em>default</em> should be a function that gets called for objects
that can’t otherwise be serialized. It should return a JSON encodable
version of the object or raise a <tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>.</p>
<p>If <em>encoding</em> is not <tt class="docutils literal"><span class="pre">None</span></tt>, then all input strings will be transformed
into unicode using that encoding prior to JSON-encoding. The default is
<tt class="docutils literal"><span class="pre">'utf-8'</span></tt>.</p>
<p>If <em>namedtuple_as_object</em> is true (default: <tt class="docutils literal"><span class="pre">True</span></tt>),
objects with <tt class="docutils literal"><span class="pre">_asdict()</span></tt> methods will be encoded
as JSON objects.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span><em>namedtuple_as_object</em> is new in 2.2.0.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.3.0: </span><em>namedtuple_as_object</em> no longer requires that these objects be
subclasses of <tt class="xref py py-class docutils literal"><span class="pre">tuple</span></tt>.</p>
<p>If <em>tuple_as_array</em> is true (default: <tt class="docutils literal"><span class="pre">True</span></tt>),
<tt class="xref py py-class docutils literal"><span class="pre">tuple</span></tt> (and subclasses) will be encoded as JSON arrays.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.2.0: </span><em>tuple_as_array</em> is new in 2.2.0.</p>
<p>If <em>bigint_as_string</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), <tt class="xref py py-class docutils literal"><span class="pre">int`</span></tt> <tt class="docutils literal"><span class="pre">2**53</span></tt>
and higher or lower than <tt class="docutils literal"><span class="pre">-2**53</span></tt> will be encoded as strings. This is to
avoid the rounding that happens in Javascript otherwise. Note that this
option loses type information, so use with extreme caution.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.4.0: </span><em>bigint_as_string</em> is new in 2.4.0.</p>
<p>If <em>for_json</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), objects with a <tt class="docutils literal"><span class="pre">for_json()</span></tt>
method will use the return value of that method for encoding as JSON instead
of the object.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.2.0: </span><em>for_json</em> is new in 3.2.0.</p>
<p>If <em>ignore_nan</em> is true (default: <tt class="docutils literal"><span class="pre">False</span></tt>), then out of range
<tt class="xref py py-class docutils literal"><span class="pre">float</span></tt> values (<tt class="docutils literal"><span class="pre">nan</span></tt>, <tt class="docutils literal"><span class="pre">inf</span></tt>, <tt class="docutils literal"><span class="pre">-inf</span></tt>) will be serialized as
<tt class="docutils literal"><span class="pre">null</span></tt> in compliance with the ECMA-262 specification. If true, this will
override <em>allow_nan</em>.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 3.2.0: </span><em>ignore_nan</em> is new in 3.2.0.</p>
<dl class="method">
<dt id="simplejson.JSONEncoder.default">
<tt class="descname">default</tt><big>(</big><em>o</em><big>)</big><a class="headerlink" href="#simplejson.JSONEncoder.default" title="Permalink to this definition">¶</a></dt>
<dd><blockquote>
<div><p>Implement this method in a subclass such that it returns a serializable
object for <em>o</em>, or calls the base implementation (to raise a
<tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt>).</p>
<p>For example, to support arbitrary iterators, you could implement default
like this:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">default</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">o</span><span class="p">):</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">iterable</span> <span class="o">=</span> <span class="nb">iter</span><span class="p">(</span><span class="n">o</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">TypeError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="nb">list</span><span class="p">(</span><span class="n">iterable</span><span class="p">)</span>
<span class="k">return</span> <span class="n">JSONEncoder</span><span class="o">.</span><span class="n">default</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">o</span><span class="p">)</span>
</pre></div>
</div>
</div></blockquote>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Subclassing is not recommended. You should implement this
as a function and pass it to the <em>default</em> kwarg of <a class="reference internal" href="#simplejson.dumps" title="simplejson.dumps"><tt class="xref py py-func docutils literal"><span class="pre">dumps()</span></tt></a>.
This is faster and more portable than subclassing. The
semantics are the same, but without the self argument or the
call to the super implementation.</p>
</div>
</dd></dl>
<dl class="method">
<dt id="simplejson.JSONEncoder.encode">
<tt class="descname">encode</tt><big>(</big><em>o</em><big>)</big><a class="headerlink" href="#simplejson.JSONEncoder.encode" title="Permalink to this definition">¶</a></dt>
<dd><p>Return a JSON string representation of a Python data structure, <em>o</em>. For
example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">simplejson</span> <span class="kn">as</span> <span class="nn">json</span>
<span class="gp">>>> </span><span class="n">json</span><span class="o">.</span><span class="n">JSONEncoder</span><span class="p">()</span><span class="o">.</span><span class="n">encode</span><span class="p">({</span><span class="s">"foo"</span><span class="p">:</span> <span class="p">[</span><span class="s">"bar"</span><span class="p">,</span> <span class="s">"baz"</span><span class="p">]})</span>
<span class="go">'{"foo": ["bar", "baz"]}'</span>
</pre></div>
</div>
</dd></dl>
<dl class="method">
<dt id="simplejson.JSONEncoder.iterencode">
<tt class="descname">iterencode</tt><big>(</big><em>o</em><big>)</big><a class="headerlink" href="#simplejson.JSONEncoder.iterencode" title="Permalink to this definition">¶</a></dt>
<dd><p>Encode the given object, <em>o</em>, and yield each string representation as
available. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">for</span> <span class="n">chunk</span> <span class="ow">in</span> <span class="n">JSONEncoder</span><span class="p">()</span><span class="o">.</span><span class="n">iterencode</span><span class="p">(</span><span class="n">bigobject</span><span class="p">):</span>
<span class="n">mysocket</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">chunk</span><span class="p">)</span>
</pre></div>
</div>
<p>Note that <a class="reference internal" href="#simplejson.JSONEncoder.encode" title="simplejson.JSONEncoder.encode"><tt class="xref py py-meth docutils literal"><span class="pre">encode()</span></tt></a> has much better performance than
<a class="reference internal" href="#simplejson.JSONEncoder.iterencode" title="simplejson.JSONEncoder.iterencode"><tt class="xref py py-meth docutils literal"><span class="pre">iterencode()</span></tt></a>.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="simplejson.JSONEncoderForHTML">
<em class="property">class </em><tt class="descclassname">simplejson.</tt><tt class="descname">JSONEncoderForHTML</tt><big>(</big><span class="optional">[</span><em>skipkeys</em><span class="optional">[</span>, <em>ensure_ascii</em><span class="optional">[</span>, <em>check_circular</em><span class="optional">[</span>, <em>allow_nan</em><span class="optional">[</span>, <em>sort_keys</em><span class="optional">[</span>, <em>indent</em><span class="optional">[</span>, <em>separators</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>default</em><span class="optional">[</span>, <em>use_decimal</em><span class="optional">[</span>, <em>namedtuple_as_object</em><span class="optional">[</span>, <em>tuple_as_array</em><span class="optional">[</span>, <em>bigint_as_string</em><span class="optional">[</span>, <em>item_sort_key</em><span class="optional">[</span>, <em>for_json</em><span class="optional">[</span>, <em>ignore_nan</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.JSONEncoderForHTML" title="Permalink to this definition">¶</a></dt>
<dd><p>Subclass of <a class="reference internal" href="#simplejson.JSONEncoder" title="simplejson.JSONEncoder"><tt class="xref py py-class docutils literal"><span class="pre">JSONEncoder</span></tt></a> that escapes &, <, and > for embedding in HTML.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.1.0: </span>New in 2.1.0</p>
</dd></dl>
</div>
<div class="section" id="exceptions">
<h2>Exceptions<a class="headerlink" href="#exceptions" title="Permalink to this headline">¶</a></h2>
<dl class="exception">
<dt id="simplejson.JSONDecodeError">
<em class="property">exception </em><tt class="descclassname">simplejson.</tt><tt class="descname">JSONDecodeError</tt><big>(</big><em>msg</em>, <em>doc</em>, <em>pos</em><span class="optional">[</span>, <em>end</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#simplejson.JSONDecodeError" title="Permalink to this definition">¶</a></dt>
<dd><p>Subclass of <tt class="xref py py-exc docutils literal"><span class="pre">ValueError</span></tt> with the following additional attributes:</p>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.msg">
<tt class="descname">msg</tt><a class="headerlink" href="#simplejson.JSONDecodeError.msg" title="Permalink to this definition">¶</a></dt>
<dd><p>The unformatted error message</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.doc">
<tt class="descname">doc</tt><a class="headerlink" href="#simplejson.JSONDecodeError.doc" title="Permalink to this definition">¶</a></dt>
<dd><p>The JSON document being parsed</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.pos">
<tt class="descname">pos</tt><a class="headerlink" href="#simplejson.JSONDecodeError.pos" title="Permalink to this definition">¶</a></dt>
<dd><p>The start index of doc where parsing failed</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.end">
<tt class="descname">end</tt><a class="headerlink" href="#simplejson.JSONDecodeError.end" title="Permalink to this definition">¶</a></dt>
<dd><p>The end index of doc where parsing failed (may be <tt class="docutils literal"><span class="pre">None</span></tt>)</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.lineno">
<tt class="descname">lineno</tt><a class="headerlink" href="#simplejson.JSONDecodeError.lineno" title="Permalink to this definition">¶</a></dt>
<dd><p>The line corresponding to pos</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.colno">
<tt class="descname">colno</tt><a class="headerlink" href="#simplejson.JSONDecodeError.colno" title="Permalink to this definition">¶</a></dt>
<dd><p>The column corresponding to pos</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.endlineno">
<tt class="descname">endlineno</tt><a class="headerlink" href="#simplejson.JSONDecodeError.endlineno" title="Permalink to this definition">¶</a></dt>
<dd><p>The line corresponding to end (may be <tt class="docutils literal"><span class="pre">None</span></tt>)</p>
</dd></dl>
<dl class="attribute">
<dt id="simplejson.JSONDecodeError.endcolno">
<tt class="descname">endcolno</tt><a class="headerlink" href="#simplejson.JSONDecodeError.endcolno" title="Permalink to this definition">¶</a></dt>
<dd><p>The column corresponding to end (may be <tt class="docutils literal"><span class="pre">None</span></tt>)</p>
</dd></dl>
</dd></dl>
</div>
</div>
</div>
</div>
</div>
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<h3><a href="#">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#"><tt class="docutils literal"><span class="pre">simplejson</span></tt> — JSON encoder and decoder</a><ul>
<li><a class="reference internal" href="#basic-usage">Basic Usage</a></li>
<li><a class="reference internal" href="#encoders-and-decoders">Encoders and decoders</a></li>
<li><a class="reference internal" href="#exceptions">Exceptions</a></li>
</ul>
</li>
</ul>
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